Float for hydroplanes, flying boats, and the like



H. HILLMANN March 3, 1931.

FLOAT FOR HYDROPLANES, FLYING BOATS, AND THE LIKE Filed June 13, 1929 w I r Patented Mar. 3, 1931 UNITED STATES PATENT OFFICE FLOAT FOR HYDRQPLANES, FLYING BOATS, AND THE LIKE Application filed June 13, 1929, Serial No. 370,683, and in Germany June 19, 1928.

' This invention relates'to floats for hydroplanes,'flyi'ng boats and the like and consists 1n a new construction of floats, said construction comprising essentially a main body and 6 a dovetail or fork-shaped stern associated with said main body. In addition to this, my invention comprises the specific'arrangement of a main keel on the main body of the float and of additional keels on said dovetail or 4 -1 fork-shaped stern as well as a specific conformation of the underside of said main body, said dovetail or'fork-shaped stern and said keels.

Prominent objects of my invention are to provide a construction of a float for hydroplanes flying boats or the like which is possessed of greatest possible stability in lateral direction, said construction permitting easy manoeuvring upon the water surface and convenient starting and landing with relatively large useful loads as compared with the dead weight of the hydroplaneor flying boat and the driving power required therefor.

Heretofore, these problems have been solved only to an insuflicient degree, the floats to be used in connection with hydroplanes' in place of the carriages usually employed with aeroplanes having ordinarily been constructed essentially in accordance with the principles of constructing high-speed water-vehicles. According to my invention far better results may be obtained, if floats are used which differ from the floats of ordinary construction in that they are constructed to the i' greatest possible extent in agreement with aerodynamic as well as in agreement with hydrodynamic requirements. Floats constructed according to my invention may fur ther be used with advantage as hulls or shells for flying boats. The floats constructed according to my invention may further successfully be used ashulls or shells of pure water-vehicles having extraordinarily high s eed.

My invention will be morefully understood" by reference .to the accompanying drawing which shows forms of a float constructed according-to my invention, the specific construction of the deck or'upper part of the float as Well as the cellular construction of the body of the float being omitted, as this s not of importance in connection with my nvention. In the drawing, Fig. 1 is a sideview of afloat constructed according to my invention, Fig. 2 atop-view on Fig. 1, Fig. 3 a top-view of a modified construction of float, Figs. land 5 are cross-sections through several forms of the main body of floats, and Figs. 6 and 7 cross-sections through several forms of the dovetail or fork-shaped sterns associated with the main body of the float. Like reference characters indicate like parts throughout the figures of the drawing.

The rear part or stern of the float a which forms part of my present invention is of special dovetail or fork-shaped construction, and consists of two parts I), b, the outer surfaces of said parts being parallel-or approximately parallel to the longitudinal axis dd of the float, or also slightly tapering towards the rear as shown in Figs. 2 and 3. An important feature of my invention consists furthermore therein, that the outer surfaces of the fork, irrespective of their tapering or parallel form, are positioned within the largest cross-section of the main body a of ,the float. The inner surfaces of the parts 6 may diverge towards the rear and towards below as indicated at g in Fig. 7. The said inner surfaces, however, may also be of straight conformation and extend in vertical direction towards below, permitting to construct the bottom of said parts 6, 6 either with a flat or V-shaned cross-sectional con- F formation, thelatter being indicated in Fig. 6. The centrally positioned main keel f of the float in this case may follow an upwardly inclined line of concave, convex or straight form, said line extending as far as to the point i of the dovetail or fork-shaped parts 1), b. The main keel may, for instance, merge towards above into the fork of the stern alonga curved line as indicated point i in Figs. 1, 2 and 3. The float furthermore may either be constructed so as to have either an entirely smooth outer surface, without any steps therein, or one or more steps may be provided either at the mainbody a of the float or at the dovetail or fork b.-b as m-.

dicated at k in Fig. 1, or one or more steps m0 may be provided on the main body a of the float or on both parts of the dovetail or fork b-b. During use on a water surface the float will be immersed into the water to a smaller or greater degree in accordance with the load temporarily imposed thereon, an average degree of immersion being indicated in Fig. 1 by the line MM which represents the water surface. The principal properties of a float constructed according to my invention in the aforedescribed manner are pointed out in the following: 1

During forward motion through the Water, the float is being lifted to a considerable degree out of the water without causing an excessive immersion of the dovetail-shaped or forked stern and without causing water to flow over said stern. At-the same time the water will move-alongg the float in .fully smooth condition, with a minimum produc tion of spray and a minimum production of waves at the front and rear part of the float. By so constructingthe float one of the most important requirements will be. fulfilled viz that during forward motion the float will be automatically lifted out of the water. "In

addition to this, landing eitheron a smooth" ormoving water surface will be essentially facilitated by constructing the float according to my invention in the aforedescribed manner. Owing to the similarity of the hydrodynamic and aerodynamic conditions, my present float likewise will offer a minimum resistance during being moved through the air, that is during the, regular flight of a hydroplane.

In addition to the aforementioned characteristic features of the float, a great stabil ity in lateral direction will result from the fact that the stern of the float is of dovetail or fork-shaped conformation.

In a modified construction, the float according to my invention may also be used as the hull or. shell of a flying boat by providing upon the parts I) whichv form the dovetail or fork-shaped stern of tlie'float' one or more fins in the form of a keel, as well as a stabiliz ing or balancingv surface which may: either pass inthe form of a continuous surface,

along the body of the float or which may be composed of a plurality of surfaces with interstices therebetween. Furthermore, one or more vertical and horizontal rudders and one or more supporting surfaces-may be provided on the body of the float. These supporting surfaces may be arranged in any suitable way, for instance, one above theotheror staggered. 'Also the supporting surfaces may be made of any suitable height and width and arranged on'the body of the float either] in'a right or acute angle thereto. Also, the motors whic h serve for driving the propelleis-which may be -.thrust-prope'llers or draw-pro llers or bothmay .be arrange above, be ow, besides ir-intermediate said part thereof. The front part of the float is preferablyma'de in. the 'formof a heavily bilged hollow frame,.while the ribs or tim bers of the main body of the float beginning at the front part are constructed in bind Water or plural V-fo'rm, the keels .n and f being used for this purpose. This conformation of the bottom of the float mayend'at a step, if such step is'provided; if no such step is used the said conformation may extend as. far as to that .point at which the bottom or main keel is carried towards above 1n the direction towards the stern. A float ofathis form is shown in section in Figs. 4

In the construction shown in the keel is sharp throughout its length so that the two parts of the dovetail or fork form an acute angle with each other. A still more favorable effect may be produced, if the keel extends in theform of .a band or the like as shown in Fig. 3, towards the dovetail or forked end of the'float, so that the inner surfaces of the dovetail or fork do no more form theapex of an angle but issue from a surface which is positioned. transversely to the main axle d-d of the float. Either 'art ofthe dovetail 'or fork-shapedrear en the float is provided with-a special keel n commencing at the front part of thefloat' and extending as far as to the end of either part I b of the dovetail'or fork-shaped-rear end; these keels n furthermore form together with the keel f a double hollow frame or a hollow frame of plural, V cross-section, while either part of the dovetail orfork-shaped end of the float is constructed in theform of a V- shaped frame as shown at h in Fig. 6.

While I have shown in the accompanying drawing and described in the foregoing spec1- fication some preferred forms of floats, boat hulls or the like, I desire of being understood that the specific disclosure is given for the purpose of exemplification only and that the scope of in invention is defined in' the appended claims in which I have endeavored to distinguish it from the-prior art, without, Y I

however, relinquishing or abandoning any .part or feature thereof;

I claim:

1. A floatifor hydroplanes andflyingboats,v

said float comprising-a main body, a forked ,stern having interior surfaces diverging towards the rear and outer surfaces positioned said main body, and a keel on either part of said forked stern, said keel extending as 2., A float for hydroplanes' and 12' essentially-within the largest cross-section of d far as to the front part of. said main body.

- boats, said float comprising a main body, a forked stern havinginterior surfaces diverging towards the rear and outer surfaces positioned etsentially within the largest crosssection of said main body, a keel on either part of said forked stern, said keel extending as far as to the front part of said main body, and a keel on said main body, said latter keel mer ingin a curved line towards above 10 into the oik of saidstern. A

, 3. A float for hydroplanes and flying boats, 'said float comprising a main body, a forked stern having interior surfaces diverging to- Wards the rear and outer surfaces positioned essentially within the largest cross-section of said main body, a keel on either part of said forked stern, said keel extending as far as to the front part of said main body, and connected with the main keel and with the outer 20 body face by bilged hollow frames on theunderside of said main body and of said stern.

v 4. A float for-hydroplanes and flying boats, said float comprising'a main body, a forked stern having Interior surfaces diverging towards the rear and issuing from a surface positioned transversely to the main axis of the float, the outer surfaces of said forked stern being positioned essentially within the larg- 30 est cross-sectionrof said main body, and a keel on either, part of said forked stern, said keel extendin as far as to the front part of said main bo y.

5. A float for hydroplanes and flying boats, said float comprising a main body, a forked stern having mterior surfaces diverging towards the rear and outer surfaces positioned essentially within the largest cross-section of said main body, a keel on either part of said 7 40 forked stern, said keel extending as far as to the front part of. said main body, and one ormore steps provided on the underside of-sa-id main-body and said stern.

In testimony whereof I flix m si ature. 4B HERMANN HILiM N.

y as 

